European 0,465,654 describes an apparatus for leveling concrete floors or the like. A rail-mounted carriage carries a horizontal and rotationally driven auger. During translatory movement of the carriage in a direction perpendicular to the axis of the auger, the rotating auger smooths unhardened concrete.
An apparatus described in U.S. Pat. No. 4,298,555 works similarly. This apparatus serves for smoothing the inner surfaces of conical concrete floors of tanks or the like. An auger rotationally driven about its axis is movable in a frame which moves around the axis of the cone, inclined at the cone's apex angle, so that, as it orbits the frame, the entire inner surface of the cone is rotationally passed over to smooth the still plastic concrete.